College of Integrated Science and Technology

NEW COLLEGES FORMED A plan to reorganize the College of Integrated Science and Technology into two colleges took effect July 1, 2012. The new colleges are the College of Health and Behavioral Studies and the College of Integrated Science and Engineering.

iPods Used to Study Listening Habits & Hearing Loss

Not many young people like being told to turn down their music, but Communication Sciences and Disorders professor Dr. Dan Halling might have a new method to make them listen.

One of Halling’s main areas of research is noise and hearing conservation, which includes the recreational noise people experience from listening to handheld music devices. The popularity of personal stereos have grown exponentially since the introduction of the Sony Walkman in 1978, and current research indicating that popular MP3 players can generate sound levels capable of causing hearing loss concerns him. Listening behaviors, such as individuals’ volume choices and duration of listening, can determine whether personal stereo users are at risk.

“Now you don’t have to be seated in a room listening to a stereo, you can walk around with music wherever you go,” Halling said, “which means you are probably increasing your exposure to noise because you’re listening to music longer during the day, and that’s especially true now with iPods.”

The study began as the project of Halling’s graduate student, Dr. Carrie Knox. As an audiology student, Knox became aware of the potential for young people's hearing to be slowly damaged by listening to loud music through MP3 players constantly present around campus. She wanted a study to explore ways to prevent this damage.

“In thinking of different approaches, I realized that the main factor was the fact that most people don't know if they are listening too loud or not - there is not really an easy way for the average person to judge,” Knox said. “I wanted to determine whether iPod listeners would choose lower, safer listening levels, in situations in which they would be more likely to listen at higher levels, if they had access to information regarding the safety of their listening level.”

The study conducted three sessions to test whether forty-eight female personal stereo listeners would change their volume to safer levels if prompted by a visual signal telling them the volume was unsafe. By placing a small probe tube microphone in a subject’s ear canal before the headphone’s ear bud, equipment could measure the sound levels right at the eardrum. Those measurements ran to a computer and software that monitored the level and displayed either a green, yellow or red dot depending on the volume’s safety level. The subject sat in front of the computer in a simulated noisy environment, and could adjust the volume wheel on their MP3 player to see the visual feedback on the computer screen.

Halling’s study observed that more listeners adjusted their volume to lower levels when they were presented with feedback than when they were not. However in subsequent sessions without visual feedback, the listeners would return to their high volume levels, suggesting that constant visual feedback would be necessary to keep listeners at safer volume levels. The study also tested whether strength of song preference would cause listeners to disregard visual feedback, and found that regardless of whether listeners “liked” or “really liked” a song, they would still lower their volume when prompted.

Halling also asked the subjects to report whether they thought the visual feedback caused them to change their listening behavior, and most agreed that seeing a red or yellow dot on the computer screen made them lower their volume. Even though four out of the forty-eight subjects said they did not change their volume regardless of the feedback, their recorded volume measurements proved that they actually did.

“That, I think, is especially significant, and makes a case for implementing that into the listening device, because even those who say they’re going to ignore it still pay some attention,” Halling concluded. “It would be so easy to put a little LED on an iPod, would cost almost nothing to do and might very well protect a lot of peoples’ hearing.”

Using all female students as test subjects created a significant limitation to the study, but Halling said that about half of personal stereo listeners randomly polled on their volume are listening at hazardous levels.

“It’s been shown in various studies that males listen to music louder than females do,” Halling said, “and so our thought was that if we only test females we’re eliminating that source of variability and then we can just focus on the visual feedback.” Halling added that he plans on conducting follow-up studies for more rounded results.

“Another limitation of our study was we used CSD students; they’ve heard so many times in class about the importance of protecting your ears and not listening to loud music that we had this subgroup that never listened to music at hazardous levels,” Halling said. “In fact one of the follow-ups we want to do is to repeat the experiment with non-CSD students who haven’t been brainwashed.”

Halling also wants to experiment with different forms of feedback, such as auditory, to see if they are as effective as visual. Knox concurred that the color-coded dots were intended to represent other possible ways to impart the warnings, and said the study suggests that a similar type of warning implemented on personal stereo devices could allow users to make informed decisions regarding their listening levels. She also agreed that the results of the study are applicable to all personal stereo users and can positively influence their listening choices.

“With proper education regarding the detrimental effect of loud music on hearing,” Knox said, “a level warning system has the potential to reduce the risk of hearing loss for many users.”